US3942912A - Method for controlling the operation of two-speed, refrigerant motor compressors - Google Patents

Method for controlling the operation of two-speed, refrigerant motor compressors Download PDF

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Publication number
US3942912A
US3942912A US05/512,084 US51208474A US3942912A US 3942912 A US3942912 A US 3942912A US 51208474 A US51208474 A US 51208474A US 3942912 A US3942912 A US 3942912A
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US
United States
Prior art keywords
motor
efficiency
compressor
high speed
low speed
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US05/512,084
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English (en)
Inventor
Richard E. Cawley
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Lennox Industries Inc
Original Assignee
Lennox Industries Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Lennox Industries Inc filed Critical Lennox Industries Inc
Priority to US05/512,084 priority Critical patent/US3942912A/en
Priority to SE7508382A priority patent/SE7508382L/xx
Priority to DK335375A priority patent/DK335375A/da
Priority to AU83604/75A priority patent/AU8360475A/en
Priority to DE19752534610 priority patent/DE2534610A1/de
Priority to FR7526104A priority patent/FR2287131A1/fr
Priority to NL7510348A priority patent/NL7510348A/xx
Priority to JP50117578A priority patent/JPS5162408A/ja
Application granted granted Critical
Publication of US3942912A publication Critical patent/US3942912A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B31/00—Compressor arrangements
    • F25B31/02—Compressor arrangements of motor-compressor units
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B49/00—Arrangement or mounting of control or safety devices
    • F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
    • F25B49/025—Motor control arrangements
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K17/00—Asynchronous induction motors; Asynchronous induction generators
    • H02K17/02—Asynchronous induction motors
    • H02K17/12—Asynchronous induction motors for multi-phase current
    • H02K17/14—Asynchronous induction motors for multi-phase current having windings arranged for permitting pole-changing
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2600/00—Control issues
    • F25B2600/02—Compressor control
    • F25B2600/025—Compressor control by controlling speed
    • F25B2600/0252—Compressor control by controlling speed with two speeds

Definitions

  • This invention relates to a method of controlling the operation of a two-speed motor compressor that may selectively be operated at a predetermined high speed or at a predetermined low speed and that is used to drive a hermetic refrigerant compressor, and more particularly, to a novel method of controlling the operation of such two-speed electrical motor, so as to attain an overall motor compressor efficiency at low speed operation which is equal to or greater than the overall motor compressor efficiency at high speed operation.
  • the novel method of my present invention is directed to a two-speed, motor compressor system of the type disclosed in U.S. Pat. No. 3,584,980.
  • the operation of the two-speed motor compressor system can be controlled such that the overall coefficient of performance (efficiency) of the system at the lower speed, i.e., during part load conditions, is equal to or greater than the coefficient of performance (efficiency) of the system at the higher speed, during peak load conditions.
  • my novel method comprises the steps of imposing a first torque load on the two-speed electric motor during peak load operation and under a given set of evaporating and condensing conditions and then imposing a second torque load on the electric motor during part load operation and under the same set of evaporating and condensing conditions such that the ratio of the second torque load to the first torque load is equal to or less than the ratio of the motor efficiency at part load operation to the motor efficiency at peak load operation.
  • an object of the present invention is to provide a novel method of controlling the operation of a hermetic two-speed, electric motor driven, refrigerant compressor so as to attain an overall compressor efficiency at low speed operation which is equal to or greater than the overall motor compressor efficiency at high speed operation.
  • FIG. 1 is a side elevational view, partially in section and with some parts broken away, of a hermetic refrigerant compressor that is driven by a two-speed electric motor.
  • FIG. 1 illustrates a two-speed motor compressor 10 of the type whose operation may be controlled by the novel method of the present invention.
  • Motor compressor 10 similar in basic design to the motor compressor described in U.S. Pat. No. 3,584,980, includes a gastight, hermetically enclosed outer casing or housing including an upper shell 12 and a lower shell 14 integrally joined to one another, as for example, by welding.
  • To the bottom of the exterior surface of the lower shell 14 are welded a plurality of legs 16 by means of which legs the compressor may be supported in an upright position within a condensing unit or an air conditioning unit.
  • a compression mechanism 18 Supported within the outer casing of the compressor 10 is a compression mechanism 18 which includes a compressor block having a crankcase portion 20 and a motor flange portion 22.
  • An annular sleeve 24 made from sheet metal surrounds the crankcase portion 20 of the compressor block and cooperates therewith to define an annular discharge gas cavity 23 in the compression mechanism.
  • a heat shield 26 is disposed about the annular sleeve in space relationship thereto.
  • the annular sleeve 24 includes an out-turned upper flange 28. Secured to the lower shell 14 of the outer casing is an annular flange member 29. Spring means 32 cooperate between the flange 28 and flange member 29 for resiliently supporting the compression mechanism 18 within the outer casing of compressor 10.
  • a plurality of radially oriented cylinders 30 are provided within the compressor block. Though a four-cylinder compressor is illustrated, it will be understood that the present invention may be used in a hermetic refrigerant compressor having other cylinder configurations. Cylinder sleeve or liners 33 are provided in each of the cylinders 30 and a piston 34 is slidably mounted for reciprocation within each of the cylinder lines 33. Each piston 34 has mounted therein a wrist pin 36 upon which is journaled one end of a connection rod 38. The other end of each connecting rod 38 is affixed to the eccentric portion 40 of drive shaft or crankshaft 42.
  • valve assembly 60 Provided at the end of each cylinder 30 for closing the end of each cylinder cavity is a valve assembly 60.
  • the valve assemblies 60 each comprise a discharge valve unit and a section valve unit operable in a known manner.
  • Each valve assembly 60 is held in place in the end of a cylinder 30 by a cylinder head or cap 62.
  • a Belleville spring 64 and a retaining ring 66 cooperate with the cylinder head 62 to maintain the head in position closing the end of the cylinder.
  • the annular space 23 provided within the compression mechanism between the compressor block and the sleeve 24 communicates each of the cylinders and receives the discharge gases from the cylinders and conveys them to the discharge line 72.
  • the drive shaft 42 is disposed in an upright position within the compression mechanism 18 and is connected at its upper end to the rotor 44 of the electric drive motor 46.
  • the motor includes a stator 48 which is supported within the motor flange portion 22 of the compressor block and the rotor 44 which is inductively connected to the stator 48.
  • the design of the motor 46 may be consequent pole, one winding configuration with the two pole (high speed) connected parallel-Y and the four pole (low speed) connected in Y series.
  • Motor 46 can be utilized to operate at a relatively high speed, i.e., on the order of 3,600 r.p.m., during two pole operation and at a lower speed, i.e., on the order of 1,800 r.p.m., during four pole operation.
  • the characteristics of one form of motor which could be utilized are as follows:HIGH SPEED Torque Minimum Minimum motorRemarks lb/ft. Voltage Speed r.p.m.
  • Enclosing the top of the motor 46 is an end cap 50 which is suitably connected to top of the motor flange portion 22 of the compressor block.
  • Drive shaft 42 is journaled at its lower end within a lower bearing 52 mounted in lower bearing head 54.
  • the lower bearing head 54 is maintained in position by a suitable wedge-lock spring or retaining ring 56 seated within an annular groove in the lower crankcase portion 20 of the compressor block.
  • the drive shaft 42 is journaled within the spaced bearings 57 and 58 in the hub portion or partition portion 21 of the compressor block.
  • Suction gas enters the outer casing or housing of the compressor via the suction line inlet 74 and flows into a first compartment defined between the outer casing and the compression mechanism below the flange 29.
  • the gas passes from the first compartment into a second compartment or annular space defined between the flanges 29 and 28 and then into a third compartment defined between the outer casing and the top of the compression mechanism 18.
  • the suction gas passes through the opening 51 in the top of the end cap 50 over the electric motor 46 for cooling same and then through the openings 76 in the compressor block into the cylinders 30.
  • the gases are compressed within the cylinders and forced through the valve assemblies 60 into the annular discharge gas cavity 23. From the annular discharge gas cavity 23, the compressed gas passes through the discharge line 72 to the condenser of the refrigeration system in which the compressor is utilized.
  • a plurality of terminals 78 are provided in the top of the upper shell 12 in order to conduct electric current from a suitable source to the electric motor 46 and to provide for connection of suitable motor protection while preserving the hermetic nature of the compressor.
  • K c is a constant which takes into account bore, stroke, etc.
  • N is the speed of the motor
  • N m is the motor efficiency
  • T is the torque imposed on the motor by mechanical load
  • the T 1 and T 2 may be set and in this instance, the motor efficiency requirement for low speed operation could be found for a given high speed motor efficiency.
  • the low speed torque will always be less than the high speed torque because in a shift from high to low speed: (a) the torque required for overcoming mechanical friction (bearings, rods, pistons, etc.) will be reduced approximately directly with the reduction in speed; and (b) the torque required for overcoming refrigerant pressure drops internally will be reduced approximately in proportion to the square of the reduction in speed.
  • the novel method of the present invention can be utilized to control the operation of a two-speed, hermetic motor compressor so as to attain an overall efficiency for the motor compressor at low speed operation which is equal to or greater than the overall efficiency for the motor compressor at high speed operation.
  • a first torque load is imposed on the motor during high speed operation and under a given set of evaporating and condensing conditions and then a second torque load is imposed on the motor during low speed operation and under the same set of evaporating and condensing conditions such that the ratio of the second torque load to the first torque is equal to the ratio of the efficiency of the motor at low speed to the efficiency of the motor at high speed.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Control Of Positive-Displacement Pumps (AREA)
  • Compressor (AREA)
US05/512,084 1974-10-04 1974-10-04 Method for controlling the operation of two-speed, refrigerant motor compressors Expired - Lifetime US3942912A (en)

Priority Applications (8)

Application Number Priority Date Filing Date Title
US05/512,084 US3942912A (en) 1974-10-04 1974-10-04 Method for controlling the operation of two-speed, refrigerant motor compressors
SE7508382A SE7508382L (sv) 1974-10-04 1975-07-23 Anordning vid kylkompressorer
DK335375A DK335375A (da) 1974-10-04 1975-07-23 Fremgangsmade til styring af driften af en elektromotor med to hastigheder
AU83604/75A AU8360475A (en) 1974-10-04 1975-08-01 Method for controlling the operation of two-speed refriger- ant motor compressors
DE19752534610 DE2534610A1 (de) 1974-10-04 1975-08-02 Verfahren zur steuerung des betriebes eines zweigeschwindigkeits-elektromotors
FR7526104A FR2287131A1 (fr) 1974-10-04 1975-08-22 Procede de commande d'un moteur electrique de compresseur
NL7510348A NL7510348A (nl) 1974-10-04 1975-09-02 Werkwijze voor het besturen van de werking van een koelmiddelcompressor met een motor met twee snelheden.
JP50117578A JPS5162408A (en) 1974-10-04 1975-09-29 Reibaiatsushukukino 2 sokudodendokino untenoseigyosuruhoho

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US05/512,084 US3942912A (en) 1974-10-04 1974-10-04 Method for controlling the operation of two-speed, refrigerant motor compressors

Publications (1)

Publication Number Publication Date
US3942912A true US3942912A (en) 1976-03-09

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Family Applications (1)

Application Number Title Priority Date Filing Date
US05/512,084 Expired - Lifetime US3942912A (en) 1974-10-04 1974-10-04 Method for controlling the operation of two-speed, refrigerant motor compressors

Country Status (8)

Country Link
US (1) US3942912A (US20030204162A1-20031030-M00001.png)
JP (1) JPS5162408A (US20030204162A1-20031030-M00001.png)
AU (1) AU8360475A (US20030204162A1-20031030-M00001.png)
DE (1) DE2534610A1 (US20030204162A1-20031030-M00001.png)
DK (1) DK335375A (US20030204162A1-20031030-M00001.png)
FR (1) FR2287131A1 (US20030204162A1-20031030-M00001.png)
NL (1) NL7510348A (US20030204162A1-20031030-M00001.png)
SE (1) SE7508382L (US20030204162A1-20031030-M00001.png)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4137014A (en) * 1975-08-04 1979-01-30 Lennox Industries, Inc. Two speed compressor with rotor support structure
EP0205670A1 (en) * 1985-06-19 1986-12-30 Whirlpool International B.V. Refrigerating or heat-pump system
US6246969B1 (en) * 1998-09-08 2001-06-12 International Business Machines Corporation Method and apparatus for testing computer cooling systems

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2496241A1 (fr) * 1980-12-12 1982-06-18 Unite Hermetique Compresseur frigorifique hermetique
DE4331625A1 (de) * 1993-09-17 1995-03-23 Teves Gmbh Alfred Elektrische Maschine zur Wandlung von elektrischer und mechanischer Energie, insbesondere radialkraftbeaufschlagter Elektromotor zum Antrieb von Pumpen

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3008629A (en) * 1957-10-03 1961-11-14 Carrier Corp Compressor
US3380650A (en) * 1967-01-12 1968-04-30 Phillips Petroleum Co Compressor control

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2243615A (en) * 1939-07-03 1941-05-27 Gen Motors Corp Motor control system
US2715204A (en) * 1954-07-06 1955-08-09 Charles S Siskind Two-speed polyphase induction motor
US3584982A (en) * 1969-01-31 1971-06-15 Arthur D Siegel Gas pump

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3008629A (en) * 1957-10-03 1961-11-14 Carrier Corp Compressor
US3380650A (en) * 1967-01-12 1968-04-30 Phillips Petroleum Co Compressor control

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4137014A (en) * 1975-08-04 1979-01-30 Lennox Industries, Inc. Two speed compressor with rotor support structure
EP0205670A1 (en) * 1985-06-19 1986-12-30 Whirlpool International B.V. Refrigerating or heat-pump system
US6246969B1 (en) * 1998-09-08 2001-06-12 International Business Machines Corporation Method and apparatus for testing computer cooling systems

Also Published As

Publication number Publication date
JPS5162408A (en) 1976-05-31
DE2534610A1 (de) 1976-04-22
DK335375A (da) 1976-04-05
FR2287131B1 (US20030204162A1-20031030-M00001.png) 1979-09-07
NL7510348A (nl) 1976-04-06
AU8360475A (en) 1977-02-03
FR2287131A1 (fr) 1976-04-30
SE7508382L (sv) 1976-04-05

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